Manufacture of integrated circuit packages may involve, among other things, the installation of heat spreaders onto the package. During an installation process, a heat spreader lid may be adhered to a substrate while the package is mounted in a process carrier. The lid is conventionally affixed to the substrate using an adhesive or a sealant. A thermal interface material may be applied between the die and the heat spreader. Thermal conductivity between the heat spreader and the die may be dependent on the application force on the lid during curing of the thermal interface material. A clip is typically used to secure the package in the process carrier and apply force to the heat spreader while the sealant-adhesive and interface material are cured. To ensure proper heat transfer from the substrate to the heat spreader, the force asserted by the clip should be maintained within an appropriate range. The use of clips and sealant-adhesive to adhere the heat spreader to the substrate presents many manufacturing and process challenges.
One challenge is that the sealant-adhesive used to secure the heat spreader to the substrate may require additional curing steps in addition to the curing of the thermal interface material. Another problem is that the sealant-adhesive sometimes delaminates the surface of the substrate, especially in highly stressed packages. Another problem is that the insertion and removal of clips requires additional handling and assembly steps increasing cost and reducing repeatability. Another problem is that the clips may change their spring/retention force over time and temperature affecting the thermal interface between the die and the heat spreader.
Thus, what is needed is a package and method to attach a heat spreader to a substrate. What is also needed is a package and method to attach a heat spreader to a substrate that reduces the number of assembly/process steps. What is also needed are a package and method to attach a heat spreader to a substrate that reduces the risk of delamination of the substrate surface. What is also needed is a package and method to attach a heat spreader to a substrate that does not require the use of clips.